(GH-1060) Add BeforeInstall parameter to Install-ChocolateyPackage.ps1

[flcdrg]

• Add a ScriptBlock parameter to Install-ChocolateyPackage.ps1 that if present, is called after download but before install.

Closes #1060

[ferventcoder]

I like it

[Mistuke]

Would it also be possible to have a BeforeUninstall? I have a package that I haven't been able to upload to Chocolatey before of the way it performs uninstalls. It seems to first move a package and then run the uninstall script. But the move would obviously fail if a file is locked, such as a service running.

A BeforeUninstall would allow me to stop and unregister the service properly before chocolatey does it's thing.

[ferventcoder]

@Mistuke that already exists, and for exactly that purpose - it's called the chocolateyBeforeModify.ps1. It needs to be in the already installed package to be called. It is run before upgrade and before uninstall. Run choco new test from the latest version of Chocolatey (v0.10.8 as of this message) and take a look at the output.

By the way, Chocolatey is actually quite good at handling locked files in the package directory, we even have tests on this. You may see some warnings and error messages but it does successfully perform upgrades with locked package files.

[Mistuke]

@ferventcoder Thanks! I didn't know this was added, I should update my chocolatey. Last time I tried it with locked files it seems to just hang on the file move. But this was a while ago. I'll try it again.

[CLAassistant]

All committers have signed the CLA.

[gep13]

LGTM!

[gep13]

@flcdrg thank you very much for taking the time to make this addition. This looks good to me, and once the CI builds are complete, I will get this merged in.

[ferventcoder]

Just a note for consistency - we put parameter docs in the order they appear. This should later be moved ABOVE IgnoredArguments.